Carbureting system



Sept. 11, 1962 M. A. ARPAIA 3,053,242

CARBURETING SYSTEM Filed Sept. 5, 1959 3 Sheets-sheet 1 z 75 M/cx/asz a. Ale/20m i 29 INVENTOR.

u 58 BY Sept. 11, 1962 M. A. ARPAIA CARBURETING SYSTEM 3 Sheets-Sheet 2 Filed Sept. 5, 1959 MOQZKZ 0. papa/,0

INVENTOR.

I in 1 7770/Q/VE4 S p 11, 1962 M. A. ARPAIA 3,053,242

CARBURETING SYSTEM F011. AZZZZEQQ /OA/ United States Patent 3,053,242 CARBURETING SYSTEM Michael A. Arpaia, 1530 Flower St., Glendale, Calif. Filed Sept. 3, 1959, Ser. No. 837,993 26 Claims. (Cl. 123122) This invention relates to carbureting systems for internal combustion engines and more particularly to an improved system of this type constructed and arranged to provide automatic positive control over the supply of combustible mixture to an engine and featuring preheating of the combustible mixture while passing in contact with a catalytic material found to enhance combustion of the mixture thereby avoiding the discharge of non-combusted hydrocarbons to pollute the atmosphere. Another important function performed by the invention is that of preventing all fuel flow to the engine during certain operating conditions, as while decelerating or while the vehicle being propelled thereby is coasting downgrade. Other important functions performed by the present fuel supply system is the automatic supply of auxiliary air under certain operating conditions; the use of waste heat of combustion to preheat the fuel mixture and to augment the effectiveness of the catalytic material; and the provision of a multiple stage control of the combustible mixture flowing to the engine.

This invention is a continuation-in-part of the invention disclosed in my co-pending application for United States Letters Patent, Serial No. 780,460, filed December 15, 1958, entitled Fuel Carbureting System (now abandoned), which application in turn is a continuation-inpart of application for United States Letters Patent, Serial No. 568,237, filed February 28, 1956, for Fuel Carbureting System, now Patent 2,864,597, granted December 16, 1958.

The present invention embodies marked improvements in the construction and operation of the carbureting system and associated accessory shown in the aforementioned earlier filed applications. For example, it has been found that highly superior results are achieved by pre-heating the combustible mixture and passing the same into contact with a suitable catalyst immediately prior to introducing the mixture into the engine cylinders. Such pre-heating not only insures complete vaporization of all particles of fuel and its more thorough mixture with the combustion air, but the catalytic material is found to have a highly beneficial effect on the oxidation of the hydrocarbon vapors. According to one preferred mode of practicing the invention, the pre-heating and catalytic treatment of the mixture is carried out in a compactly designed preheating assembly through which the mixture is passed after leaving the venturi of the carburetor and before its entrance into the combustion chambers of the engine. However, it is to be understood that portions of the catalyst may be present in the combustion chamber and in the exhaust duct thereby to promote and assist in the more complete and efiicient consumption of the fuel before discharge of the products of combustion to the atmosphere.

A material found to have a highly beneficial catalytic effect on and to promote the oxidation of hydrocarbon vapors is copper and its oxides. Inasmuch as copper has excellent heat conducting proper-ties this material may serve in a dual capacity as a catalyst and as the material from which the heat exchanger used to pre-heat the combustible mixture is constructed. As herein shown by way of example, the heat exchanger comprises a serpentine copper tube arranged to separate the combustible mixture from the heating medium such as the exhaust gases issuing from the engine combustion chambers and passing to the exhaust system of the engine. However, it is to be understood that additional quantities of copper in 3,053,242 Patented Sept. 11, 1962 either solid or finely divided state may be located in the combustible mixture circuit and arranged to be heated in any suitable manner including use of engine waste heat or any other suitable source of heat.

Copper is not only highly effective itself as a catalyst but readily forms an oxide, particularly when heated in the presence of oxygen, which oxide fractures easily and sheds from the parent material in very small discrete particles thereby serving to provide a continuous renewal supply of both the oxide and of the freshly exposed surface of the parent copper material. Additionally, the shedding copper oxide prevents the accumulation of a deposit of lead and other precipitants from the hydrocarbon fuel. It has not been determined with certainty whether the copper oxide alone, the newly exposed copper surface or a combination of these two factors provide the high efiiciency catalytic effect on the hydrocarbons although it has been definitely established that the presence of the heated copper material in contact with unconsumed hydrocarbons is highly effective in promoting oxidation of the fuel and in improving the operating efficiency of the engine generally.

Another important feature of the invention is the use of an improved multiple-stage control valve located on the discharge end of the carburetor, and operable, when closed, to cut off all fuel flow to the engine, including idling fuel. This two-stage valve is arranged for operation selectively by the vehicle operator or in response to pressure conditions within the intake manifold, the adjustment of the operating linkage being such that pressure conditions indicative of engine idling and deceleration operating conditions are effective to close the twostage valve, either partially or fully as will be described in detail in following portions of this specification. Alternatively, this valve can be opened or closed and otherwise controlled by the operator at all times.

According to a simplified embodiment of the invention, the positive action fuel cut-off valve control and heat exchange accessory assembly provided by the invention is insertable as a unit in lieu of the throttle valve assembly commonly employed to connect the engine carburetor to the intake manifold. The two-stage mixture control valve forming an important part of the auxiliary unit performs the function of the usual carburetor throttle valve and, in addition, certain other functions essential to the practice of this invention and lying outside the capabilities of conventional throttle valve structures.

It is a primary object of the present invention to provide an improved carbureting system for an internal combustion engine of the type used to propel motor vehicles and featuring means for automatically interrupting all fuel flow to the engine so long as certain engine oper ating conditions prevail.

Another object of the invention is the provision of means for subjecting unconsumed hydrocarbon vapors supplied to an internal combustion engine to the catalytic effect of heated copper and oxides of copper.

Another object of the invention is the provision of means associated With an internal combustion engine for subjecting hydrocarbon vapors supplied thereto to the catalytic effect of heated copper and oxides of copper.

Another object of the invention is the provision of a carbureting system for an internal combustion engine wherein hydrocarbons being supplied to the combustion chambers pass in contact with a hot catalytic agent effective to enhance chemical reaction of the hydrocarbons with oxygen.

Another object of the invention is the provision of a carbureting system for use with an internal combustion engine wherein the combustible fuel mixture is passed in heat exchange with a catalytic maintained hot by waste heat of the engine.

Another object of the invention is the provision for supplying a fuel, air and catalytic material mixture to the combustion chambers of an internal combustion engine.

Another object of the invention is the provision of an accessory designed to be interposed in the fuel supply circuit Of an engine and incorporating a heat exchanger constructed to pass the combustible fuel mixture in heat exchange with the products of combustion issuing from the engine.

Another object of the invention is the provision of a carbureting system making use of engine waste heat to preheat a combustible mixture being supplied to the engine.

Another object of the invention is the provision of an improved method of pre-conditioning a combustible fuel and air mixture flowing to an internal combustion engine.

Another object of the invention is the provision of a unitary auxiliary assembly arranged to be inserted between a carburetor exhaust outlet and the inlet to an engine intake manifold and including means for automatically discontinuing all flow of fuel to the engine so long as certain engine operating conditions prevail.

Another object of the invention is the provision of a multiple stage mixture flow control valve located between the carburetor outlet and the engine cylinders adapted to be controlled selectively by conditions prevailing within the intake manifold or by the operator through the conventional acceleration control linkage.

Another object of the invention is the provision of an auxiliary unit insertable between a carburetor and an intake manifold and arranged to utilize portions of the exhaust gases to preheat the combustible mixture flowing to the engine.

Another object of the invention is the provision of a combustible fuel preheater utilizing exhaust gases diverted from the exhaust system and including automatic valve means responsive to exhaust pressure conditions to regulate automatically the flow of gases so diverted.

Another object of the invention is the provision of an improved carbureting system for use on motor vehicles and including means operable automatically in response to engine operating conditions to control fuel flow in accordance with power requirements and operable to discontinue all fuel flow during engine deceleration thereby effecting operating economies and obviating the discharge of incompletely consumed fuel to the atmosphere.

Another object of the invention is the provision of a carburetor accessory responsive to manifold pressure to actuate fuel and air control mechanisms in a manner supplementing and overriding, under certain operating conditions, the fuel and air control provided by the usual engine carburetor assembly.

Another object of the invention is the provision of pressure-responsive means subject to engine manifold conditions operable to actuate a plurality of valves to effect control of fuel and air flow to the engine in accordance with actual power requirements and additionally to provide positive fuel cutoff while the vehicle propelled thereby is decelerating and coasting down-grade, together with automatic means for regulating the manifold pressure during deceleration.

Yet another object of the invention is the provision of automatic fuel shut-off mechanism for discontinuing all fuel flow to the engine during deceleration in combination with means for restoring fuel flow automatically for engine idling requirements while the vehicle is still underway and even though the operators foot is fully removed from the accelerator.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawings to which they relate.

Referring now to the drawings in which a preferred embodiment of the invention is illustrated:

FIGURE 1 is a side elevational view of essential components of the accessory provided by this invention with parts broken away to show certain constructional details, the parts being shown in their operating position for engine deceleration operating conditions, the dot and dash line showing of certain parts being the positions thereof under engine idling conditions;

FIGURE 2 is a fragmentary view similar to FIGURE 1 but showing the position of certain of the parts during full acceleration operating conditions;

FIGURE 3 is a fragmentary view taken along the broken line 3-3 on FIGURE 1;

FIGURE 4 is a fragmentary cross-sectional view taken along line 44 on FIGURE 1, and showing the multiplestage mixture valve fully closed;

FIGURE 5 is a cross-sectional view through the heat exchanger along line 5-5 on FIGURE 1;

FIGURE 6 is a cross-sectional view taken along line 66 on FIGURE 4;

FIGURE 7 is a cross-sectional view similar to FIG- URE 6 but showing the position of the carburetor throttle valve and of the multiple-stage valve during full acceleration operating conditions; and

FIGURE 8 is a partial cross-sectional view through a modified embodiment of the invention showing the position of the multiple-stage valve during idling operating conditions.

Referring more particularly to FIGURES 1 to 4, the fuel control and pre-conditioning accessory unit provided by this invention and designated generally 10 is shown clamped between the flanged end 11 of engine intake manifold 12 and the flanged end 13 of carburetor throttle valve housing 14 by means of through bolts 15 extending through the accessory housing and through flanges '11 and 13. It is pointed out that in the embodiment here illustrated accessory device 10 is designed for use with a V-8 type engine having a pair of identical carburetors arranged in closely-spaced parallel relation between the two banks of cylinders with each supplying a separate bank. To this end accessory 10 as here shown includes a pair of multiple-stage valve assemblies mounted on a common shaft operable selectively by the accelerator linkage or by automatic means responsive to the pressure within one of the two engine intake manifolds. It is pointed out, however, that accessory .10 is equally suited for use with a larger or smaller number of carburetors, it merely being desirable to provide a separate set of multiplestage valves for each carburetor barrel and for each associated intake manifold.

One of the two identical carburetor fuel mixture discharge ducts is indicated at '16 and its mounting flange 17 is shown secured to flange '18 of throttle valve housing 14 as by cap screws 19. The fuel and air mixture flows downwardly through throttle valve housing 14 under the control of a conventional butterfly valve 20 pivotally supported on a shaft 21. Operating lever 23 fixed to the outer end of shaft 21 is normally biased clockwise by a spring 24 having its remote end anchored to the assembly casing by a headed pin 25. The linkage for operating the throttle valve will be described presently.

As is most clearly shown in FIGURE 3, accessory 10 includes a generally rectangular housing 28 having formed integral with one end thereof a generally cylindrical housing 29 enclosing the pressure responsive actuator for the multiple-stage combustible mixture shut-off valve forming an important feature of the invention. The interior construction of valve housing 28 will be best understood from FIGURES 3 and 4 wherein it is seen to be formed in three principal parts comprising a lower or heat exchange housing 30, an intermediate partition 31, and an upper valve housing 32, all having close fitting surfaces held in sealed engagement by through bolts 15. Desirably, suitable gaskets are interposed between the several parts and particularly between housing sections 30 and 32 and flange 11 of the intake manifold and flange 13 of the throttle valve housing. Preferably, these gaskets are of heat insulating material to limit the transfer of heat from the manifold to the carburetor.

Heat exchange housing incorporates the catalytic material found to have such a pronounced elfect in promoting the union of the hydrocarbons with oxygen. A particularly convenient and effective manner of effecting this contact with a catalytic agent is accomplished in the structure here illustrated by using the catalytic agent to form a serpentine tube and using this tube as the heat conducting means separating the combustible mixture from the hot exhaust gases issuing from the engine and providing a convenient and inexpensive mode of maintaining the catalytic agent at an eflicient operating temperature. However, it is to be understood that additional catalytic agent in the form of heat conducting fins, partitions or granular material distributed along the interior of tube 35 may be employed.

One arrangement of the tubular heat exchanger and catalytic agent 35 is shown in FIGURE 5, it being noted that a partition 36 divides housing 30 into separate chambers in order to maintain proper control over the fuel mixture supplied from each carburetor to its associated bank of engine cylinders. As shown, serpentine tube 35 includes a pair of bight portions 37, 38 located closely beside the outer side wall of housing 30. The midportion of bight 37 is connected through a conduit 39 to the upper side of an automatic flow control valve 40 (FIG- URE l) pivotally supported in an open-ended housing 41 connected by cap screws 42 to a midsection of the engine exhaust line 43 leading from engine exhaust manifold 44. The midportion of bight 38 is similarly connected by conduit 45 to the discharge side of automatic valve 40.

Valve 40 is mounted on a shaft 4-6 to the outer end of which is secured a lever arm 47 slidably and adjustably supporting thereon a weight 48 effective to bias valve 40 to closed position when the engine is not operating. However, when the engine is operating the exhaust pressure in manifold 44 is effective to pivot valve 40 toward open position by an amount depending upon exhaust pressure conditions. In consequence, a portion of the exhaust gases are constrained to flow through conduit 39, heat exchanger tubes 35 and back by way of conduit 45 into the low pressure side of valve 40 in exhaust conduit 4-3.

Partition 31 separating heat exchange housing 30 from valve housing 32 is provided with a pair of large area passages 50 here shown as rectangular in shape and each having an area corresponding to that of vertical passage 51 providing communication between carburetor duct 16 and inlet 52 leading into valve housing 32. Pivotally supported within housing 32 are a pair of multiple-stage valves designated generally 55, each valve assembly including a rigid valve supporting arm 56 having one end fixed to a shaft '57 journalled horizontally lengthwise of housing 32 with one end opening through the housing wall in a manner best shown in FIGURE 3. Shaft 57' pivots about its axis through an angle of approximately 90 degrees from its fully closed position during deceleration (FIGURE 6) and the fully opened position during maximum acceleration illustrated in FIGURE 7.

The valve members per se of each assembly are loosely mounted on each of the arms 56 and include a large area plate valve 58 of thin flexible material sufficiently larger than mixture passageway 59 through partition 31 as to seat and be supported on the peripheral edges of the passageway in the manner made clear by FIGURE 3. The means for loosely supporting valve 58 from bracket arm 56 comprises a pair of pins fixed to the opposite sides of the valve member and extending loosely through openings in bracket 56, valve 58 being urged away from bracket 56 by light springs 60 encircling pins 59. The upper ends of pins 59 are upset or otherwise formed as indicated at 62 to hold the same assembled to arm 56. Valve members 58 are each provided with a small diameter circular opening 63 centrally thereof having several purposes including the supply of idling fuel and air to the engine when main valves 58 are closed. Opening 63' is controlled by a thin disc valve 64 having a short pin 65 fixed to its center and extending loosely through an opening in the bottom of a well 66 formed in bracket arm 56 (see FIGURE 6). A light coil spring 67 urges valve 64 toward seating engagement with the rim of opening 63 in the main valve plate. The upper end of pin 65 is headed over, as is indicated at 68 in FIGURE 6,, to hold idling valve 64 in assembled position.

Referring now more particularly to FIGURES 1, 3 and 4, the automatic pressure-responsive means operable to control the position of the multiple-stage valve assembly 55 is seen to include a cylindrical housing 29 integral with one end of valve housing 32 with its longer axis extending horizontally across the top of the engine. A cylindrical bore 73 interiorly ofhousing 29 slidably seats a piston 74 mounted on a piston rod 75 slidably supported in an end cap 76 secured to one end of housing 29. Piston 74 is secured to the threaded inner end of rod 75 by a nut 77 while the other thread end 78 of rod 75 has a snug frictional fit with a shouldered nut 79 threaded thereover. The latter is adjustable to vary the eifective force on a spring 86 encircling a piston rod in the area between the shoulder on nut 79 and end cap 76 and tending to shift piston 74 to the right as viewed in FIGURE 1. Once the proper adjustment of spring 89 has been obtained, the exposed end of the piston rod may be enclosed by cupshaped end cap 82 held in place on housing 29, as by cap screws 83. Caps 7 6 and 82 are preferably provided with vent openings 84 connecting one end of piston 74 and the interior of cap 82 to the atmosphere.

The left hand end of the piston chamber 29 as viewed in FIGURE 3 has rotatably supported therein a crank arm 83 mounted on a crankshaft 89 having one end 96 opening through the side wall of housing 29. Connecting rod link 91 has one end connected to the bifurcated end 92 of piston rod 75, as by pin 93, while the other end of link 91 is connected to the bifurcated upper end of crank 88, as by a pin 94. Fixed to the outer end of crankshaft 89 in any suitable manner is a suitably shaped cam 96 cooperable with arm 97 of a bell crank 98 fixed to the outer end of valve shaft 57. The other arm 99 of bell crank 98 is provided with a short arcuate slot 100 seating the hooked end of a linkage rod 101 having its other end pivotally supported in the outer end of the throttle valve operating arm 23. The free end of hell crank arm 97 is connected to the usual vehicle accelerator pedal 102 (FIGURE 1) through any suitable linkage such as a lever 103 pivotally supported at 104 and having its lower end connected to bell crank arm 97 by link 105.

Provision for admitting supplemental air to prevent excessive lowering of the manifold pressure during deceleration, and for other purposes, includes an automatically operating valve disc 108 fixed to crankshaft 89 and having a close sliding fit with surface 109 on the exterior face of piston housing 29. Plate 198 is provided with a pair of air ports 110, 111 spaced somewhat more than 90 degrees apart circumferentially of disc 108 and respectively adapted to register simultaneously with the outer ends of a pair of air passages 112 and 113, passage 112 opening into one of the mixture passageways 50 in' partition 31 and passage 1113 opening into the other of passageways 50 in the manner made clear by FIGURE 3. A pressure equalizing duct 114 also extends through partition 31 and piston housing 29 with its inner end opening into the intake manifold by way of the heat exchange housing 30 and mixture port 50 in partition 31. The outer end 115 of duct 114 (FIGURES 3 and 4) opens into the left hand end of piston chamber 73 to the end that this end ofthe piston will be subject to the manifold pressure at all times irrespective of the adjusted position of valve assembly 55 and of throttle valve 20. Preferably, auxiliary air valve disc 198 and the ports car- -7 rled thereby are protected from damage and from the entry of foreign matter by guard screening 117.

Referring more particularly to FIGURES 6 and 7, it will be noted that the idling fuel supply includes a passage 118 extending from the main fuel supply in the carburetor proper downwardly through the side wall of throttle valve housing 14 and into the fuel mixture passage 51. The flow of the idling fuel is controlled by a needle valve 119 of usual construction having a knurled head 120.

Referring now to FIGURE 8, there is shown a simplified embodiment of the present invention wherein the same or similar parts are designated by the same refere'nce characters but distinguished therefrom by the addition of a prime. The FIGURE 8 construction differs from that shown in FIGURES 1 to 7 primarily in the elimination of throttle valve housing assembly 14 and in the modification of the idling fuel supply in such manner that the multiple-stage valve assembly 55 provides full control over both the combustible fuel mixture and idling fuel requirements at all times. Not only does the simplified construction effect a considerable saving in the number of components required, but of particular importance, this embodiment functions to preheat the fuel mixture as well as to provide complete control over the supply thereof to the engine. Furthermore, this unitary assembly is insertable in lieu of the conventional throttle valve without modification in the overall height requirements of either the engine, the air filter, or any other auxiliaries associated with the carbureting system.

It will be noted that idling fuel duct 118 in carburetor duct 16 opens into an extension of duct 118' located in valve housing 32', the idling fuel control valve 119' being located in an extension 122 formed in partition 31'. The outlet end 123 of the idling fuel duct opens upwardly into the valve chamber at a point closely adjacent main valve 58'. In the position of the parts shown in FIGURE 8, idling mixture control valve 64' is shown in elevated position above port 63' in main valve 58'. Under these conditions idling fuel supplied through duct 118' and outlet end 123 thereof merges with combustion air supplied by way of carburetor duct 16' for passage through port 63 and over the hot heat exchange ducting 35' in heat exchange chamber 30'. The fuel so preheated is routed directly to the engine cylinders by way of intake manifold 12'. Other operating positions of the multiplestage valve assembly 55' will be explained in greater detail below.

In the operation of the described carbureting device, nut 79 controlling the pressure of spring 80 of the manifold pressure responsive device is so adjusted that a normal intake manifold suction pressure of 20.5 inches of mercury under engine idling conditions is effective to hold piston 74 in the position indicated in dot and dash lines in FIGURE 1. In this position of the parts, it is to be understood that the 20.5 inch manifold pressure is efiective on piston 74 to hold crank 88 rotated suificiently clockwise from the full line shown in FIGURE 1 for the end of cam 96 to contact arm 97 of hell crank 98 to hold the latter rotated through a small angle counterclockwise about the axis of valve shaft 57 and sufficiently to occupy the dot and dash line position shown in FIGURE 1. The auxiliary air control disc 108 will then be rotated to a position wherein the air inlet ports 110 and 111 barely are out of registry with the air ducts 112, 113, respectively, with the result that all air required for idling engine requirements is supplied in conventional manner by leakage past the imperfectly closing throttle valve 20. Even though throttle valve 20 appears to be closed, considerable quantities of air lead past its peripheral edges for admixture with idling fuel flowing downwardly through duct 118. It is pointed out that the low intake manifold pressure of 20.5 inches of mercury is effective to hold the large and flexible plate valves 58 tightly sealed against their respective seats provided at the upper ends of ports 50, However, the small idling fuel control valves 64'. are held positively in the open position shown in FIGURE 8 by the described manifold pressure of 20.5 inches of mercury acting on piston 74 holding the latter in the dot and dash line position shown in FIGURE 1. In this position of the piston, crank 88 and eccentric 96 fixed thereto are rotated to a position effective to hold arm 97 of bell crank 98 rotated counterclockwise to the dot and dash line position illustrated in FIGURE 1. Under these conditions, arm 56' of the valve assembly is likewise rotated slightly counterclockwise thereby holding idling fuel valves 64' elevated slightly above port 63. Accordingly, the low pressure condition existing in the heat exchange housing 30, though tending to close idling valve 64', cannot do so. Moreover, this low pressure condition in the intake manifold and in the heat exchange housing is communicated in part to the valve housing 32' through ports 63 and is effective to vaporize the idling fuel issuing from supply passage 123. Likewise, this low pressure condition is effective to draw atmospheric air downwardly through carburetor duct 16' opening into the top of valve housing 32' for admixture with the idling fuel. As this mixture passes downwardly through the heat exchanger it passes in direct contact with the hot tubes 35 causing every particle of fuel to be vaporized for thorough mixture with the air prior to its delivery to the engine cylinders through intake manifold 12.

As has been indicated above, tube 35 not only serves to preheat the fuel mixture and assure vaporization of droplets of hydrocarbon, but exposes this mixture to intimate contact with copper oxide and with the freshly exposed surfaces of copper as small particles of the oxide continually shed from the copper and pass into the combustion chambers along with the preheated fuel and air mixture. The shedding particles of copper oxide are predominantly minute in size and remain in suspension while being transported into the combustion chamber and from there to the ambient atmosphere along with the exhaust gases. It is believed that the presence of the minute particles of copper oxide in the combustion chamber is fully as important in promoting oxidation of the fuel as is the contact with the catalyst outside the combustion chambers, but irrespective of this and of the mechanics involved, it is known that highly superior results are achieved by use of the described structure and method of supplying fuel to an internal combustion engine.

It is found that the throttling effect produced by the passage of air and fuel mixture through ports 63 into the very low pressure zone therebelow causes the air to expand. This expansion is accompanied by a marked reduction in the temperature of the air thereby limiting to some degree the temperature rise which would otherwise occur because of the very hot condition of the combined catalytic agent and heat exchange conduit 35' following a period of engine operation under moderate to high load operating conditions. Another beneficial effect of this expansive cooling of the mixture is the maintenance of partition 31 in a cooler condition thereby minimizing interference with the flow of liquid fuel through supply passages 118' and 123.

The engine continues to operate in the manner described so long as the accelerator pedal remains in its retracted position and the intake manifold pressure remains at its normal idling operating value in the vicinity of 20.5 inches of mercury. Should the operator depress the accelerator pedal, bell crank 98 is thereby rotated counterclockwise to rotate valve shaft 57' and the attached valve supporting arm 56 thereby forcibly opening the main valve plates 58' from sealing engagement with the top of passageways 50'. The increased flow of air and fuel thereby occasioned increases the richness of the fuel mixture with the result that the engine speed and load carrying ability rises sharply and in accordance with the amount of fuel and air actually supplied to the engine. Likewise, the pressure in engine exhaust manifold 44 increases and rotates valve 40 counterclockwise to pass the much greater volume of exhaust gases produced by the engine. However, the pressure drop or differential across valve 40 is effective to circulate a greater volume of exhaust gases through conduit 39, catalytic heat exchanger tubes 35" after which the partially cooled exhaust gases return to exhaust conduit 43 on the low pressure side of valve 40 by way of conduit 45. Under normal to high operating speeds of the vehicle engine, heat exchange conduit 35 may be maintained at a temperature as high as 1200 degrees F., at which temperature the catalytic agent provided by the copper employed in the heat exchanger is extremely effective in vaporizing all particles of the liquid fuel and in preheating this fuel as well as the combustion air with the result that extremely efiective and efficient combustion occurs upon entry of the fuel into the engine cylinders.

Should the operator remove his foot from accelerator 102, as when slowing down or when coasting down-grade, the suction pressure developed within intake manifold 12 may be and is usually as low as 25 inches of mercury. This low pressure is effective on piston 74 to move it to the left in opposition to spring 80 to the full line position illustrated in FIGURE 1 carrying with it cam 96 and the auxiliary air control valve plate 108 until auxiliary air ports 110 and 111 in valve plate 108 are in accurate registry with air ducts 112 and 113 respectively. Auxiliary air is then admitted into the heat exchanger and into the intake manifold 12 to limit the pressure reduction characteristic of decelerating operating conditions. The low pressure in manifold 12' at this time is effective to hold both main valve 58' and the idling fuel or secondary valve 64' tightly and positively closed cutting off all fuel flow, including both the main fuel supply and the idling fuel supply provided through passages 118' and 123.

Valves 58 and 64' remain closed until the vehicle approaches the end of deceleration operation, whereupon the low pressure conditions in the intake manifold start rising to a point where spring 80 of the pressure responsive device becomes effective to shift piston 74 to theright as viewed in FIGURE 1. As this occurs, link 91 operates through crank 88 to rotate cam 96 clockwise into engagement with arm 97 of hell crank 98. This rotation forcibly rotates valve shaft 57' counterclockwise, as viewed in FIGURES 1 and 8, thereby forcibly rotating arm 56' to open idling valves 64. Slight opening of valve 64' is adequate to admit idling fuel and air mixture to intake manifold 12 and to the engine cylinders and this occurs while the vehicle is under way. Accordingly, the fuel mixture is immediately ignited and the engine begins to idle long before the vehicle comes to a stop.

If the accelerator pedal 102 is not depressed to admit additional fuel and air to the engine, the engine continues to operate under idling conditions. However, under normal conditions, the operator will depress the foot pedal to maintain the vehicle at a desired speed. Depression of accelerator 102 rotates the valve assembly toward its open position thereby increasing the fuel and air supply. Under acceleration operating conditions, the manifold pressure is at a value of about 3 inches of mercury and spring 80 is then effective to hold piston 74 fully retratced to the position shown in FIGURE 2. Any movement of piston 74 occurring so long as the engine is operating at acceleration or cruising speed is immaterial and neither affects the fuel and air flow nor interferes in any way with the control of the fuel and air to the engine under the control of the operator through adjustment of accelerator pedal 102. In this connection it is pointed out and emphasized that the rotated position of shaft 57' by the accelerator linkage is effective to control the volume of fuel and air mixture flowing to heat exchanger 30' and to intake manifold 12' without need for the usual carburetor throttle valve such as throttle valve 20 in the first described embodiment.

The operation of the embodiment illustrated in FIG- URES 1 to 7 is very similar to that described above in connection with FIGURE 8, the main difference being that the operation of the accelerator pedal 102 acts through the accelerator linkage connections to actuate the carburetor throttle valve 20 relied upon primarily to control the fuel and air mixture flow when the engine is operating at other than idling speed. In other words, it will be understood that throttle valve 20 functions as do conventional carburetor throttle valves and that the automatic pressure responsive valve designated generally 10 provides an overriding and supplemental control for the mixture flow under certain operating conditions as, for example, when the foot is removed from the accelerator pedal 102. Under these conditions throttle valve spring 24 is effective to rotate bell crank 23 clockwise to close throttle valve 20, it being understood that even in its closed position some leakage air flow takes place past its peripheral edges.

In the closed position of throttle valve 20 the mixture flows to intake manifold 12 under the control of the pres sure responsive piston 74. Since the pressure in the intake manifold differs widely depending on whether the vehicle is coasting or at stands-till with the motor idling, it will be understood that the position of the pressure responsive two-stage valve assembly 55- likewise varies over a wide range. If, for example, the vehicle driven by the engine -is coasting down-grade, its speed of travel will depend on the grade, the previous rate of speed before the operators foot is removed from the accelerator, the nature of the road surface, and other factors. At higher deceleration speeds the intake manifold pressure will be at its minimum value, that is, in the vicinity of 25 inches of mercury. This low suction pressure will be effective to hold both the main valve 58 and the idling fuel control valve 64 tightly seated to cut off all fuel flow to the engine. Under these conditions, piston 74 will be in the full line position illustrated in FIGURE 1 and the auxiliary air ports 110 and 111 in valve disc 108 will be in full registry with the ends of air passages 112, 113, respectively, to admit a flow of air into the intake manifold thereby limiting the pressure reduction in the manifold. All fuel flow to the engine will remain cut off unless the operator should depress accelerator 102 to rotate shaft 57 counterclockwise as viewed in FIGURE 1 to forcibly open the valves.

It would be very difficult to open both valves 64 and 58 simultaneously due to the large area thereof and the very low pressure prevailing in the intake manifold. As will be best understood from FIGURE 8, the headed upper end of pin 65 fixed to valve 64 is contacted by arm 56 prior to the contact of this arm with the headed end 62 of the pin 59 fixed to the larger valve 53 with the result that smaller valve 64 opens before larger valve 58. Immediately that the smaller valve opens to admit atmospheric air through carburetor duct 16, the low pressure condition in the intake manifold is relieved making it possible to open the larger valve easily and without excessive stress on the valve parts and the connecting operating linkage. Also the considerably higher pressure condition now prevailing in the intake manifold allows spring to move piston 74 to the right as viewed in FIGURE 1 rotating valve disc 109 clockwise to move auxiliary air ports 110, 111 out of registry with the inlets to air ducts 1 12, 113, respectively. Normal cruising operation of the motor then ensues as the two-stage valve assembly 55 is rotated upwardly by the manually controlled accelerator and piston 74 resumes its normal cruising position at the right hand end of cylinder bore 73'.

If it is assumed that the deceleration of the motor and of the vehicle is permitted to continue without interruption, the position of the parts referred to above will continue to be maintained until near the end of the deceleration period. As the end of deceleration approaches, the decreasing speed at which the momentum of the vehicle tends to turn the engine results in a slight rise of the intake manifold pressure toward. atmospheric pressure. This pressure rise allows spring 80 to shift piston 74 from the full line position shown in FIGURE 1 to the dot and dash line position. This small movement of piston 74- to the right serves to rotate cam 96 clockwise beneath arm 97 of bell crank 98 causing shaft 57 to be rotated counterclockwise sufliciently for valve supporting arm 56 to elevate the small valve '64 to the position of the similar valve 64 in FIGURE 8, valve 64- being forcibly held in this position by spring 80 and the connected parts including piston rod75, link 91, crank 88, cam 96, bell crank 98 and valve shaft 57.

It is also pointed out that the exhaust gas pressure in the exhaust manifold 44 will vary depending upon the engine operating speed and the volume of gases being exhausted from the engine. The position of valve 40 in exhaust pipe 43 is dependent on the gas pressure acting on the rear side of this valve as well as upon the position of counterweight 4-8 on valve arm 47. It will be understood that a coil spring or its equivalent may be used in lieu of counterweight 48 to urge valve 40 toward closed position and to resist full opening of valve 40 during operation of the engine. Either arrangement assures an adequate circulating supply of hot exhaust gases in intimate contact with the catalytic agent employed in heat exchanger 35 to the end that the fuel mixture flowing to the intake manifold will be properly pre-conditioned and preheated and that all liquid fuel will be fully vaporized. Under normal engine operating conditions the combined catalytic agent and heat exchanger 35 should operate at a temperature between 500 degrees F. and 1200 degrees F., the higher temperature being associated with higher engine speeds and engine loads. As will be appreciated, the heat exchanger operating temperature can be varied by the volume of hot exhaust gases circulated in contact with catalytic material 35 and controlled by regulating the position of valve 40.

Although the preferred method of preheating the fuel and air mixture is by the use of exhaust gases, it is to be recognized that the hot engine cooling water may be circulated through heat exchanger 35 in lieu of the exhaust gases. However, this method of preheating is subject to the disadvantages imposed by the much lower temperatures and the much larger conduits required to provide for a sufficient water flow to preheat the fuel mixture. It is also to be recognized that the catalytic material may be heated other than by waste heat from the engine as by burning portions of the fuel in a special burner serving to maintain the catalyst at a desired and eflicient operating temperature.

While the particular improved carbureting method and system for internal combustion engines herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. In a carbureting system for an internal combustion engine having a carburetor assembly positioned to deliver a combustible fuel and air mixture to the engine intake manifold, that improvement which comprises a combustible mixture preheating and flow control assembly adapted to be interposed between said carbureting system and said intake manifold, said assembly including a housing having a mixture inlet port adapted to be connected to the discharge of said carburetor assembly and a mixture outlet port adapted to be connected to a vehiclepropelling engine intake manifold, a normally open mixture flow control valve positioned between said mixture inlet and outlet ports, means responsive to sub-atmospheric pressure conditions within said intake manifold for adjusting the position of said mixture flow control valve, and means for preheating the combustible mixture in the presence of a combustion promoting catalyst and delivering the same to the engine to operate the same.

2. The improvement defined in claim 1 characterized in that said mixture preheating means includes means utilizing waste heat from the engine derived from the combustible mixture flowing through said preheating and flow control device.

3. The improvement defined in claim 1 characterized in that said mixture preheating and flow control device comprises a unitary assembly adapted to be inserted as a unit between said carbureting assembly and the inlet of the engine intake manifold.

4. The improvement defined in claim 1 characterized in that said flow control valve is a multiple stage valve including a main valve and a secondary valve arranged to open and close sequentially with respect to each other to control the flow of said combustible mixture.

5. The improvement defined in claim 4 characterized in that said main and secondary valves are arranged in series, and means operable to open said secondary valve to initiate renewed flow of combustible mixture to the engine before opening said main valve.

6. The improvement defined in claim 4 characterized in that said main and secondary valves comprise thin flexible plate members arranged in superimposed aligned but spaced relation when open, said valves being adjustable relative to one another and to a seat for the main valve to vary the flow of combustible mixture and being closeable against said seat and against one another to prevent all flow of said combustible mixture in the fully closed positions thereof.

7. The improvement defined in claim 1 characterized in the provision of means for passing hot fluid from said engine in heat exchange with said combustible mixture and with a combustion promoting catalyst to preheat said mixture before introducing said mixture into the engine cylinders.

8. The improvement defined in claim 1 characterized in the provision of means for conducting hot exhaust gases discharging from the engine cylinders into heat exchange with said combustible mixture and a combustion promoting catalyst at a point between said flow control valve and said intake manifold.

9. The improvement defined in claim 8 characterized in that a portion only of the engine exhaust gases are conducted in heat exchange with said combustible mixture and with said combustion promoting catalyst.

10. In combination with a combustible fuel and air mixture supply system for an internal combustion engine of the type using a fuel and air carbureting device discharging directly into the intake manifold of an engine, that improvement which comprises a mixture flow control auxiliary unit adapted to be inserted between said car- 'bureting device and said intake manifold, said auxiliary unit having a two stage valve therein including a large area main valve and a relatively small area pilot valve including means for opening and closing said valves sequentially and in reverse order on opening and on closing, manually operable means for controlling said valves, and automatic means responsive to operating pressure conditions in the engine intake manifold for controlling said valves independently of said manually operable means.

11. The combination defined in claim 10 characterized in that said manually operable means for controlling said two-stage valve includes a foot operable engine accelerator pedal.

12. The combination defined in claim 10 characterized in the provision of valve means for admitting auxiliary air to said intake manifold at a point between said twostage valve and the inlet to the engine cylinders to support engine idling operation when said two-stage valve is closed.

13. The combination defined in claim 10 characterized in the provision of a cylindrical chamber within said auxiliary unit, spring-biased pressure responsive means movably supported within said chamber with one side exposed to atmospheric pressure and the other side in communication with the interior of the intake manifold, and means operatively connecting said pressure responsive means to said two-stage valve and operable to close the latter fully under predetermined low pressure operating conditions within said manifold indicative of deceleration engine operating conditions.

14. The combination defined in claim 13 characterized in the provision of means for adjusting the spring bias on said pressure responsive means to render the latter effective to close said two-stage valve at a preselected manifold pressure and cut oil the flow of combustible mixture to the engine by way of said valve.

15. The combination defined in claim characterized in that said two-stage valve includes a pair of flexible valve plates, one of said plates being of relatively large area and having a flow port therethrough, and the other of said valve plates being aligned with the flow port of said first-mentioned plate and movable relative thereto for selectively cutting off all mixture flow or permitting controlled mixture flow therethrough.

16. That improvement in the mode of operating a vehicle propelling engine to prevent the admission to and exhaust therefrom of unconsumed fuel which improve ment comprises: means for passing a variable volume mixture of fuel and air to the engine to satisfy power requirements of the vehicle under normal cruising conditions, means responsive to depression of the intake manifold pressure characteristic of deceleration operation of the vehicle to positively cut off all flow of said fuel and air mixture during deceleration and to re-establish the flow of the fuel and air mixture as the manifold pressure rises to a predetermined valve, and means for utilizing waste heat of combustion of burned portions of said fuel and air mixture to preheat newly formed portions of the mixture while in intimate contact with hot catalytic material immediately prior to the introduction of said mixture into the vehicle engine.

17. That improvement defined in claim 16 characterized additionally by means for lay-passing fuel for engine idling operation to the engine intake manifold along with a quantity of auxiliary air while said engine is operating free of load at idling speed and While the intake manifold pressure is lowered sufficiently to maintain the normal flow of fuel and air mixture positively cut off.

18. That improvement defined in claim 16 characterized additionally by means for re-establishing normal flow of fuel and air mixture after a period of no flow sequentially and in stages by first opening a small area flow port and thereafter opening a relatively large flow port.

19. That improvement defined in claim 16 characterized additionally in that said manifold pressure responsive means includes means responsive to depressed intake manifold pressure in cooperation with atmospheric pressure to prevent flow of said fuel and air mixture to the engine during periods of low pressure operating conditions within the engine intake manifold.

20. That improvement defined in claim 18 characterized additionally in that said manifold pressure responsive means includes means responsive to depressed intake manifold pressure conditions characteristic of certain engine operating conditions to close said large area value while leaving said small area valve at least partially open thereby causing the flow of fuel and air to be throttled through said small area port controlled by said smaller valve.

21. That improvement defined in claim 16 characterized additionally in that said manifold pressure responsive means includes means responsive to depressed intake manifold pressure conditions characteristic of certain engine operating conditions to restrict the flow passage for the fuel and air mixture whereby the flow of said mixture into the depressed pressure zone Within the intake manifold causes fuel components of said mixture to expand and vaporize more fully than would otherwise occur.

22. An auxiliary fuel control unit adapted for insertion between the flanged coupling normally interconnecting a c-arbureting device to the intake manifold of a vehicle-propelling engine, said fuel control unit comprising a low-height housing adapted to be interposed between the flanges of said carbureting device and of said intake manifold and cooperable therewith to convey a fuel and air mixture from said device to said manifold, said housing having movably supported adjacent a valve seat therein a pair of series-connected sequentially-operable valves for controlling the flow of said mixture, heating means within said housing for heating said mixture on the downstream side of said valves while in contact with hot copper oxide, and means responsive to a predetermined lowering of the pressure on the discharge side of said valves for closing said valves and holding the same closed until forcibly opened or until said depressed pressure condition ceases to exist.

23. An auxiliary unit as defined in claim 22 characterized in that said heating means for heating said mixture and said copper oxide normally operates at a temperature substantially in excess of 500 F.

24. An auxiliary unit as defined in claim 22 characterized in the provision of manually operable linkage means connected to said valves and operable in opposition to said pressure responsive means to open said valves sequentially notwithstanding the forcible closing thereof by the depressed pressure operating conditions Within the intake manifold.

25. An auxiliary unit as defined in claim 22 characterized in that said heater comprises walls of copper in heat exchange on one side with the fuel and air mixture flowing through said housing and in heat exchange on the other side with hot exhaust gases discharging from said engine and flowing to the engine exhaust gas duct for flow to the atmosphere.

26. In a fuel supply system for the engine of a motor vehicle, that improvement which comprises a normally closed pressure responsive valve in the engine exhaust gas duct, the exhaust gas pressure in said duct under engine operating conditions being efiective to open said valve toward the fully open position thereof, means for supplying a fuel, copper oxide and air mixture to the engine, and means for lay-passing exhaust gases from the engine side of said valve in heat exchange relation with said fuel, copper oxide and air mixture to preheat the mixture and then back to said exhaust gas duct on the opposite side thereof from said engine.

References Cited in the file of this patent UNITED STATES PATENTS 1,048,224 Stevens Dec. 24, 1912 1,643,072 Iesdale Sept. 20, 1927 1,795,037 Portail Mar. 3, 1931 1,852,918 Chandler Apr. 5, 1932 1,970,169 Godward Aug. 14, 1934 2,073,649 Price Mar. 16, 1937 2,231,605 Stephenson et al Feb. 11, 1941 2,362,163 Shipman Nov. 7, 1944 2,590,377 Cater Mar. 25, 1952 2,609,806 Winkler Sept. 9, 1952 2,640,472 Bicknell June 2, 1953 2,964,597 Arpaia Dec. 16, 1958 FOREIGN PATENTS 7,018 Great Britain Mar. 23, 1904 28,404 Great Britain Dec. 13, 1906 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,053,242 September 11, 1962 Michael A. Arpaia It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 13, line 35, for "valve" read value line 64, for "value" read valve Signed and sealed this 26th day of March 1963.

(SEAL) Attest:

ESTON G-. JOHNSON DAVID L. LADD Attesting Officer Commissioner of Patents 

